I have had a vp shunt for over 40 years, personally unlike it seems like a lot of people who a shunt, it doesn't seem like these neurosurgeons have a clue. I have had 3 revisions and a replacement. I have had 5 headaches in my life, unfortunately but fortunately surgery correct it every time and I have never had any after effects. Based on the information you stated, the shunt was not properly placed. Forget a second opinion, you need a first opinion and the placing of the shunt needs to be corrected. I am not a doctor, however I think I have a little experience, also it sounds like your neurosurgeon is a putz and is in it for the money, sorry to say....any questions just ask.